Door latching mechanisms with at least two latch assemblies are useful in certain applications where it is desirable to have multiple latch points. One such increasingly important application is in the area of walk-in bathtubs. Walk-in bathtubs feature a door with a gasket. The door opens either inwardly or outwardly. When the door is open, the user can basically walk into the bathtub without having to step over the otherwise relatively high wall of the bathtub. When the door is shut, its gasket will ride against a complementary opening is the tub, thereby forming a watertight seam. Walk-in bathtubs are growing in popularity with invalid patients, people with ambulatory problems, and those who simply prefer easy ingress and egress from a bathtub.
When a walk-in bathtub is filled with water, a considerable amount of water pressure builds up from the 40-50 gallon capacity contained therein. If the door of a walk-in accidental pops open, or the gasket leaks, there is a potential for considerable water damage. Even a slight leak or any dripping whatsoever is unacceptable to manufacturers and consumers alike of walk-in bathtubs. Accordingly, many walk-in bathtubs are fitted with more than one latch to ensure good sealing along the entire door/door frame interface. For ease of operation, some prior art multi-latch door latching mechanisms had one latch assembly carry the door handle (master latch assembly) with the other latch assembly (slave latch assembly) being operably connected to the master latch assembly with a linkage.
With prior art door latching mechanisms having at least two latch assemblies connected with a linkage, if the linkage breaks, gets out of alignment, or otherwise becomes disabled, it is possible that one or more of the latch assemblies can become stuck in a locked position, preventing the door from being opened. Another problem with prior art door latching mechanisms having at least two latch assemblies is that they are not generally designed to provide for even closing of the door along the location of each latch, and thus, leakage along the seal can sometimes occur.
There accordingly remains a need for new designs of door latching mechanisms having at least two latch assemblies that prevent inadvertent locking of the door upon failure of the linkage, and also provide even sealing of a door with a door frame.